Sylvania



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G. W. MORRIS 82; W. H. LAWRENCE.

ELLIPTIG SPRING.

No. 393,569. Patented NOV. 27, 1888.-

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GEORGE WV. MORRIS AND WILLIAM H. LAWRENCE, OF PITTSBURG, PEN N- SYLVANIA.

ELLlPTiC SPRlNG.

SPECIFICATION forming part of Letters Patent No. 393,569, dated November 27, 1888.

Application filed July 24, 1888. Serial No. 280,879.

' leaves will have freer and more perfect flexibility under the compressing action of the spring and theirliability to be broken greatly lessened.

Our improvement consists of a graduated tightly-clamping band for the plates or lifts which compose the spring-that is to say, a keystone-shaped band having its greatest width next to the plate which receives the load directly and forms the inner side of the arch and the longest plate of the spring, while the tapering end of the band is at the outer side of the arch and next the shortest plate. In this arrangement the tapering end forms the bearing-support for the spring, which is made up of a number of plates or lifts in the same manner as now in use, the shortest of the said plates or lifts being about one-fifth the length of the inner plate that receives the load and forms a hearing at each end for the body of the vehicle. In this class of springs it is well known that under compression the tendency of the main or inner bearingplate is to leave the upper corners or edges of the usual square band (now used) in attaining toward a straight line, thus relieving the pressure of the band on the top or inner bearing-plate, while the short plates or lifts are unduly forced against the lower corners or edges of the square band, thus rendering them liable to breakage at such edges. By arranging the clamping-band 'so that its apex will be at the outside of the arch and form the fixed bearing-support for the spring and its tapering edges standing with the graduation of the re-enforcing lifts this undue pressure is decreased proportionally on all the short lifts, easier motion is imparted, and lia- (No model.)

bility of snapping off the shorter lifts consequently reduced. By such improvement the cost is not increased nor the carrying capacity reduced, and a more durable spring is produced.

The accompanying drawings illustrate our improvement applied to an elliptical halfspring, and in which- Figure 1 represents a side view of a semielliptical spring with our improved leaf'confining band. Fig. 2 is a view of the upper side of the spring, and Fig. 3 a view of the under side thereof.

In the drawings, a is the main plate, being the longest of the nest of leaves which compose the spring A, and b is the shortest plate or leaf of the nest. The plates or leaves are placed upon each other in the usual manner and number, according to the use for which the springs are designed, the plates gradually decreasing in length from the longest to the shortest.

The clamping-band B has the form of what is known as the keystone or an arch, and is placed and bound upon the leaves in the middle of their length with its narrowest end D at the shortest leaf or plate of the spring and the widest end E at the longest leaf or plate. The band has a width at its narrowest end about half that of its widest end, so that it has a graduated clamping action upon all the graduated plates of the spring alike, thereby allowing the shortest leaves to have freer play and to yield more evenly to pressure upon the ends of the spring than would be possible with a band of even width at all the plates. The band is shrunk or otherwise secured upon the plates, and for heavy springs-such as are used for engines and tendersourimprovement is of special andimportant advantage for durability and for giving an easy movement.

Referring now to Fig. 1, let the horizontal line 2 2 represent the action of the spring in attaining a straight line, and it will beseen that the greatest strain at the clamping-band will be upon the shortest plate or leaf of the spring, and now applying this maximum strain to a clamping-band of equal width the short plates are liable to break at the edges of the band, because the binding-action of the band is equal upon the plates at all points in a straight line and the spring is thereby measurably stiffened; but applying this maximum strain upon the keystone or graduated clamping-band it will be found that the stiffness of the spring will be greatly relieved as to all its plates or leaves and their liability to snap or break at the binding-edges 2 of the clamp greatly lessened.

The importance of this improvement is enhanced in the proportion in which it helps to save a single leaf from being broken, because when this occurs the spring is destroyed.

It will be understood that by having the tapering sides 0 of the band standing away from the bearing-plate a of the spring the width of the clamping-surface of the sides of the band decreases with the length of the lifts, and as the latter only re-enforce or contribute their force to support the bearing-plate a, which receives the load directly, the liability of the lifts to snap along the tapering sides 2 of the band is greatly diminished and the elasticity of the spring is increased.

What we claim as new is 1. A banded elliptical half-spring composed of a bearing-plate, a, and graduated lifts, and having a tapering grippingband arranged with its apex forming the fixed bearing for the spring and for said lifts at the outer side of 30 the arch, and having its widest end at the bear- 7 ing-plate of the spring or inner side of the arch, whereby the gripping-surface for the lifts. 

